Operations of at least 23 planes from Kolkata airport were disrupted for three hours in the wee hours today due to dense fog and poor visibility. <br/><br/>Airport officials said, at least 13 outgoing domestic flights could not take off and 10 other domestic flights could not land at the airport due to visibility going below 300 metre.<br/><br/>Flight operations were suspended at 5.50 am as the visibility went too low for CAT-2 Instrumental Landing System to work at NSC Bose International airport. <br/><br/>The delayed flights include Air India flights from Kolkata to Mumbai, New Delhi and Silchar. <br/><br/>Ten domestic incoming flights kept hovering in the sky and began to land after the visibility improved at 8:40 am and operations were normalised.<br/><br/>The Officials, however added that no flight was diverted and no international flight was affected.<br/>